B4X

Get PDF Signer Certs

See more PDF Signatures Examples

This example demonstrates how to validate the signatures in a PDF and also shows how to get B4X

Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

Dim pdf As ChilkatPdf
pdf.Initialize("pdf")

'  Load a PDF that has cryptographic signatures to be validated
success = pdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf")
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


'  Each time we verify a signature, information about the signature is written into
'  sigInfo (replacing whatever sigInfo previously contained).
Dim sigInfo As ChilkatJsonObject
sigInfo.Initialize

'  Iterate over each signature and validate each.
Dim numSignatures As Int = pdf.NumSignatures
Dim validated As Boolean = False
Dim cert As ChilkatCert
cert.Initialize("cert")
Dim i As Int = 0
Do While i < numSignatures
    validated = pdf.VerifySignature(i, sigInfo)
    Log("Signature " & i & " validated: " & validated)

    '  After calling VerifySignature, you can get the signer certificate by calling
    '  GetSignerCert with the same index. 
    success = pdf.GetSignerCert(i, cert)
    If success <> False Then
        Log("PDF signer certificate: " & cert.SubjectDN)
    End If


    i = i + 1
Loop

Log("Finished.")